3999997 has 4 divisors (see below), whose sum is σ = 4005436. Its totient is φ = 3994560.

The previous prime is 3999971. The next prime is 4000037. The reversal of 3999997 is 7999993.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2414916 + 1585081 = 1554^2 + 1259^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3999997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3999917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1404 + ... + 3157.

It is an arithmetic number, because the mean of its divisors is an integer number (1001359).

Almost surely, 2^3999997 is an apocalyptic number.

It is an amenable number.

3999997 is a deficient number, since it is larger than the sum of its proper divisors (5439).

3999997 is an equidigital number, since it uses as much as digits as its factorization.

3999997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5438.

The product of its digits is 1240029, while the sum is 55.

The square root of 3999997 is about 1999.9992499999. Note that the first 3 decimals coincide. The cubic root of 3999997 is about 158.7400655118.

It can be divided in two parts, 3 and 999997, that added together give a 6-th power (1000000 = 10⁶).

The spelling of 3999997 in words is "three million, nine hundred ninety-nine thousand, nine hundred ninety-seven".